Errors in medication provided to a patient are recognized as a serious, and potentially avoidable, problem associated with the delivery of health care.
Medication errors are estimated to account for 7,000 deaths annually, and adverse drug events cause more than 770,000 injuries and deaths each year. Patients who suffer from unintended drug events remain in the hospital an average of 8 to 12 days longer than patients who did not experience such mistakes. Two recent studies, one conducted in Colorado and Utah and the other in New York, found that adverse events occurred in 2.9 and 3.7 percent of hospitalizations, respectively.
Infusion devices are believed to account for up to 35% of all medication errors that result in significant harm (Class 4 and 5). Mistakes typically arise from manually programming incorrect infusion parameters, and the failure to ensure the right patient receives the right medication. The most common error is manually programming infusion parameters such as delivery rate, drug, and drug dose, into the device.
Unfortunately, there is currently no commercially available device capable of reliably determining both the identity and concentration (and thus dosage) of a wide variety of unknown intravenous fluids as they are being delivered to a patient.
Although systems for verifying the presence of a drug or its concentration have been proposed, the majority of these systems rely solely on optical methods (such as optical spectroscopy). For example, U.S. Pat. No. 6,847,899 to Allgeyer et al. describes a spectroscopic analysis device for identifying medications in an IV solution. Similar systems are described in U.S. Pat. No. 7,154,102 to Poteet et al. (florescence spectroscopy), PCT/US2007/087062 and PCT/US2006/036612 by Potuluri et al. (verification of solid drug identity by optical spectroscopy) and U.S. Pat. No. 7,317,525 to Rzasa et al.
Because these systems rely on spectroscopic analysis, they typically suffer from the limitations inherent in optical systems. These limitations may include a limited ability to distinguish between compounds, and particularly mixtures of compounds having multiple components, as well as difficulty in reliably distinguishing concentrations of different compounds.
Thus, there is a need for devices, systems and methods for checking or confirming an IV drug composition has been correctly formulated, e.g., by a pharmacy by directly sampling and testing the formulation. There is also a need to confirm that a drug being delivered to a patient is correct and corresponds to the prescribed medication, by directly sampling and testing the formulation. Drugs are often formulated in low ionic strength liquids. Such fluids have proven extremely difficult to examine electrically, because of the low ionic strength. Thus, it would be particularly helpful to provide devices, systems and method of applying immittance spectroscopy to low ionic strength liquids.
In addition, it would be helpful to provide a method of determining the identity and composition of IV drug waste. Hospitals and other institutions are increasingly required to document proper disposal of environmentally sensitive waste and monitor for diversion of scheduled drugs. Thus, it would be helpful to provide devices, systems and method for confirming the amount and type of drug waste, and providing an accurate record of drug waste collected and/or disposed of. It would also be beneficial to sort drug waste so that different drug waste could be disposed of appropriately according to the compounds in the waste fluid.
Described herein are immittance spectroscopy devices and methods that use multiple electrical immittance measurements to determine the identity, and in some variations concentration, of one or more components of a medical solution such as an intravenous solution.